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Myrmecol. News 28: 25-33 doi: 10.25849/myrmecol.news_028:025 13 September 2018 Original Article ZooBank LSID: 0FFDEA17-75EA-419B-A732-3E17D4C316CA

A mixed colony of Tetramorium immigrans Santschi, 1927 and the putative social parasite Tetramorium aspina sp.n. (Hymeno­ptera: Formicidae) Herbert C. Wagner, Celal Karaman, Volkan Aksoy & Kadri Kiran

Abstract

Mixed ant colonies have long fascinated biologists since they are often examples of social parasitism. From the ge- nus Tetramorium Mayr, 1855, two types of social parasitism are well known: dulosis and inquilinism. We present a nest record from Turkey comprising workers of T. immigrans Santschi, 1927, workers and a single gyne of a new species, and brood in commonly used nest chambers. We interpret the new species as a social parasite and describe it as T. aspina sp.n. Three characteristics indicate a morphological degeneration of the worker caste: Workers of T. aspina sp.n. have strongly reduced propodeal spines, larger intranest morphological variability than workers of the T. caespitum complex sensu Wagner & al. (2017: Myrmecological News 25: 95-129), and a larger proportion of these workers have an aberrant propodeum (“propodeal syndrome”) compared with workers of the T. caespitum complex. The discovery of T. aspina sp.n. raises interesting questions concerning the characterization of its socially parasitic life history and its evolutionary origin.

Key words: Morphometrics, propodeal spine, intranest morphological variability, worker caste degeneration, new species, Tetramorium caespitum complex, non-cryptic pavement ant, Turkey.

Received 6 March 2018; revision received 29 August 2018; accepted 30 August 2018 Subject Editor: Christian Rabeling

Herbert C. Wagner (contact author), Department of Ecology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria; ÖKOTEAM – Institute for Animal Ecology and Landscape Planning, Bergmanngasse 22, 8010 Graz, Austria. E-mail: [email protected]

Celal Karaman, Volkan Aksoy & Kadri Kiran, Faculty of Science, Department of Biology, Trakya University, 22030 Edirne, Turkey. E-mail: [email protected], [email protected], [email protected]

Introduction Symbioses among ant species have fascinated biologists inquilinism (permanent social parasitism without slavery). for centuries (Huber 1810, Darwin 1859, Forel 1874, The latter two occur in the species-rich genus Tetramorium Fabre 1879, Hoffer 1889, Wasmann 1891, Emery 1909, Mayr, 1855 leading to its central role in social parasitism Faber 1967, Kutter 1968, Hölldobler & Wilson 1990, research (Forel 1874, Emery 1909, Crawley & Donist- Heinze 1996, Seifert 2007, Buschinger 2009). According horpe 1913, Emery 1913, Kutter 1950, Stumper 1951, to Hölldobler & Wilson (1990), there are two types of ant Kutter 1968, Hölldobler & Wilson 1990, Sanetra & al. symbioses: compound nests and mixed colonies. In com- 1999, Seifert 2007, Buschinger 2009, Ward & al. 2015). pound nests, two ant species share a nest space or nest close We describe Tetramorium aspina sp.n., a non-cryptic to one another and occasionally interact, but they keep and species belonging to the T. caespitum group sensu Bolton rear their brood separately (Gray & al. 2018). In contrast, in (1995). We argue that the putative mixed colony indicates mixed colonies, two ant species share a nest space, interact social parasitism using T. immigrans Santschi, 1927, a frequently, and store brood in a common area where they member of the T. caespitum complex sensu Wagner & al. are cared for by one or both species. Usually, myrmecolo- (2017), as host. gists explain the origins of mixed colonies via one of three Materials and methods types of social parasitism (Hölldobler & Wilson 1990, Seifert 2007, Buschinger 2009): temporary social parasit- Sample: In 2012, 888 Tetramorium nest samples were ism, dulosis (permanent social parasitism with slavery), or collected from the East Black Sea Region in Turkey (leg. K.

© 2018 The Author(s). Open access, licensed under CC BY 4.0 https://creativecommons.org/licenses/by/4.0 Statistics: Intranest morphological variability of Tetramorium aspina sp.n. was compared with that of the T. caespitum complex for 30 characters. In T. aspina sp.n., pairwise differences of morphometric and meristic character values of workers were calculated. By using 18 workers, there were (182 + 18) / 2 - 18 = 153 pair com- binations. Negative difference values were multiplied by -1 to build arithmetic means of only positive values. The same was repeated with 478 intranest worker pairs of the T. caespitum complex (using data of Wagner & al. 2017). The procedure described here was performed for absolute values and for indices (i.e., values divided by the a b head index CS). In a t-test (two-sided, type one), mean intranest character differences of T. aspina sp.n. and the Fig. 1: Transversal section of mesosoma at level of propodeal T. caespitum complex were compared (Tab. 1). Frequency spiracles. In workers with the “propodeal syndrome”, the pro­ differences in the occurrence of propodeal syndrome be- podeal narrowing leads to a step at meeting point of metapleuron tween T. aspina sp.n. and the T. caespitum complex were and propodeum with an angle of around 90° (a). In normal evaluated using a chi-square-test. Statistics were done in workers, the step is missing or less pronounced and the angle SPSS Statistics v19. The alpha used was 0.05. is more obtuse (b). Treatment of species names: For all Tetramorium species listed for Europe, the Mediterranean Basin, North Africa, Middle East, Turkey, transcaucasian countries, Kiran, C. Karaman & V. Aksoy). This area of northeastern Iran, and the Arabian Peninsula (Borowiec 2014), either Turkey has thus far received little attention from myr- recent taxonomic revisions (Sanetra & al. 1999, Güsten & mecologists (cf. Kiran & Karaman 2012). Seven of the 888 al. 2006, Csősz & al. 2007, Csősz & Schulz 2010, Sharaf samples were taken from near the Giresun-Dereli-Çamlı & al. 2012, Borowiec & al. 2015, Radchenko & Scupola Village (50 km SSE Giresun, 40.4767° N, 38.5108° E, 2015, Sharaf & al. 2015, Borowiec & al. 2016, Salata & 1953 m above sea level). One of the seven samples proved to Borowiec 2017, Sharaf & al. 2017, Wagner & al. 2017) be a nest comprising two species. The nest was excavated or original descriptions were analyzed. Additionally, all thoroughly and a large number but not all of the available Tetramorium type images available on AntWeb were in- individuals of both the putative parasitic species and the vestigated. Species that were neither yellowish nor lacked putative host were collected. distinct propodeal spines were excluded from our list of Morphological investigation: Data were collected possible conspecifics. The only species similar toT. aspina using a LEICA MZ16 A high-performance stereomicro- sp.n. was investigated by taking morphometrics of images scope with a magnification range of 80 - 294×. The host on AntWeb. species was determined using the key of Wagner & al. Results and discussion (2017). Morphometric and meristic data of 18 workers of Tetramorium aspina sp.n. from the type nest were taken. Mixed colony record: About 500 (56%) of the 888 Te- Most characters were defined byWagner & al. (2017); due tramorium nests sampled in the East Black Sea Region to the partial lack of propodeal spines, SPWI could not belonged to the Tetramorium caespitum complex. Near be measured in workers. One morphometric character the Giresun-Dereli-Çamlı Village we found five nests of is newly introduced: PSW, which is the maximum outer T. cf. impurum (Foerster, 1850), one of an unidentified distance between the edges of the left and right propo- Tetramorium species, and one nest containing the two deal spiracles, measured in dorsal view. In the gyne, the species T. immigrans and T. aspina sp.n. Workers of the depth of median petiole and postpetiole insection were latter were distinguishable in the field from host workers also measured. Additionally, unilateral numbers of teeth by their yellowish color and smaller size. The nest was and ommatidia were counted. All bilateral characters constructed under a stone that was 30 × 20 cm in diameter except PnHL (see definition in Wagner & al. 2017) were and 5 - 10 cm high. The colony comprised similar propor- measured from both sides and an arithmetic mean was tions of workers of each species. Workers of both species calculated. In addition to morphometric measurements were evenly distributed over all nest chambers. The brood and meristics, qualitative morphological characters were chambers comprised many larvae and one pupa. Based on collected. As “propodeal syndrome” we define an aberrant the characteristic shape of the propodeum, the pupa could propodeal narrowing, which is found in workers of T. be assigned to T. aspina sp.n., but we could not assign the aspina sp.n. as well as in the T. caespitum complex. The larvae to a species. If the larvae included individuals from propodeal narrowing leads to a step at the meeting point T. immigrans, our observation could be interpreted as a of metapleuron and propodeum with an angle of around case of a mixed colony. Alternatively, if the larvae only be- 90° (Fig. 1a). In normal workers, the step is missing or less longed to T. aspina sp.n., both species could be considered pronounced and the angle is more obtuse (Fig. 1b). as co-inhabiting a compound nest. The only non-worker

26 Tab. 1: Mean intranest character differences ofTetramorium aspina sp.n. and the T. caespitum complex sensu Wagner & al. (2017). Cases with larger differences in theT. caespitum complex in bold. Intranest differences in T. aspina sp.n. are significantly larger.

Absolute differences Index differences Characters T. aspina sp.n. T. caespitum T. aspina sp.n. T. caespitum (n = 18) complex (n = 478) (n = 18) complex (n = 478) CL 35.4 30.2 0.0115 0.0081 CW 40.0 30.4 0.0115 0.0081 dAN 11.3 10.0 0.0073 0.0068 EL 10.6 7.6 0.0100 0.0062 EW 6.6 5.9 0.0066 0.0048 FL 15.6 13.3 0.0110 0.0080 HFL 38.5 31.8 0.0210 0.0169 MC1TG 1.4 2.4 0.0020 0.0034 ML 53.9 41.3 0.0247 0.0192 MPPL 17.2 12.5 0.0140 0.0083 MPSP 19.6 17.7 0.0207 0.0124 MPST 14.3 10.0 0.0142 0.0069 MtpW 32.4 17.6 0.0367 0.0102 MW 30.6 22.9 0.0173 0.0110 PEH 15.7 12.2 0.0121 0.0092 PEL 9.4 9.0 0.0094 0.0084 PEW 24.6 13.4 0.0269 0.0106 PLSP 18.7 11.4 0.0217 0.0123 PLST 14.6 10.6 0.0151 0.0094 PnHL 29.1 19.0 0.0374 0.0232 PoOc 10.8 12.5 0.0140 0.0097 POTCos 2.4 1.6 0.0037 0.0020 PPH 13.4 13.4 0.0162 0.0120 PPL 7.4 7.6 0.0091 0.0084 Ppss 17.1 15.0 0.0249 0.0206 PPW 22.9 15.8 0.0229 0.0135 PreOc 11.7 9.3 0.0086 0.0069 RTI 22.5 14.9 0.0157 0.0115 SLd 29.5 25.7 0.0209 0.0145 SPST 8.3 10.5 0.0128 0.0097 individual in the nest was a queen of T. aspina sp.n. found iterranean basin, and adjacent regions (for details, see in a chamber 30 - 35 cm below the ground level. A T. immi- Taxonomic description of Tetramorium aspina grans queen was not found. The revelation of the parasitic sp.n. below). The only similar species, Tetramorium biology of T. aspina sp.n. demands further investigation. nitidissimum Pisarski, 1967 from Firyuza (25 km W Ash- Pure nest records of T. aspina sp.n., slave raids, or a lack gabat, Turkmenistan), shares the character combination of function of the worker caste would demonstrate tem- of very short propodeal spines and a yellowish color in porary social parasitism, dulosis, or inquilinism with a workers. However, images of two workers from AntWeb worker caste, respectively (Hölldobler & Wilson 1990, (CASENT0904825, CASENT0917069) allowed a distinct Buschinger 2009). differentiation from the new species described here (for Morphology: The morphometric investigation of details, see Differential diagnosis). Additionally, the the new species revealed obvious differences from most type gyne of T. nitidissimum (CASENT0917070) is very other Tetramorium species known from Europe, the Med- different from the gyne ofT. aspina sp.n. Thus, we consider

27 Fig. 2: A general view of the type locality of Tetramorium aspina sp.n.

T. aspina sp.n. as a non-cryptic and non-described species. It belongs to the T. caespitum group sensu Bolton (1995). Based on their yellowish color and small eyes, workers are probably subterranean foragers. Morphological degeneration: We found three con­spicuous characteristics of Tetramorium aspina sp.n. workers: (i) They are nearly the only Tetramorium workers in Europe, Anatolia, and adjacent regions lacking propo- deal spines. Myrmecologists interpret propodeal spines often as defense against vertebrates (Dornhaus & Powell 2009, Ito & al. 2016, Sarnat & al. 2016, Blanchard & Moreau 2017, Sarnat & al. 2017). There is a trade-off between defensive traits like the sting and spines. Inter- estingly, an evolutionary loss of spines is more than twice as likely as a gain (Blanchard & Moreau 2017). In the T. caespitum complex, a relation between ecological niche and the evolution of propodeal spines has been discerned, and hence a selection pressure on this morphological structure and factors linked to ecology has been suggested (Wagner & al. 2018). We speculate that the loss of spines in T. aspina sp.n. workers might represent a degeneration linked with their parasitic life history. (ii) Intranest mor- phological character differences (Tab. 1) were significantly higher than in the T. caespitum complex (absolute values, t-test, p < 0.00001; indices, t-test, p < 0.00001). Morpho- logical characters with a high intranest variability were shown to be not under strong stabilizing selection pressure Fig. 3: Holotype worker of Tetramorium aspina sp.n. in (a) full (Imai & al. 2016). (iii) Eleven of 18 investigated workers face, (b) dorsal, and (c) lateral views (photographer Leo Kuzmits). (61%) had the propodeal syndrome. In contrast, in the T. caespitum complex, this syndrome was found only in four of 968 workers. Thus, it is more frequent in our sample morphological degeneration of workers in Tetramorium of T. aspina sp.n. (qui-square-test, p < 0.00000000001). aspina sp.n. To summarize, we propose three traits that at least Outlook: Since all known parasites using Tetramo- partly indicate a morphological degeneration of workers: rium as host show a more derived morphology than T. the lack of propodeal spines, the high intranest morpholog- aspina sp.n. (see Kutter 1968, Hölldobler & Wilson ical variability, and the high frequency of workers with the 1990, Seifert 2007, Buschinger 2009, Ward & al. 2015), propodeal syndrome. Future research should investigate if no species comparable with T. aspina sp.n. has ever been the parasitic biology and associated decrease of stabilizing reported. Maybe, T. nitidissimum could be another exam- selection on morphology (cf. Imai & al. 2016) explains the ple. Recent studies elucidated the evolutionary origins of

28 ant social parasites in distantly related genera (Jansen & al. 2010, Rabeling & al. 2014, Leppänen & al. 2015a, b, Prebus 2017, Sanllorente & al. 2018), and inferring the evolutionary origin of T. aspina sp.n. is a high priority for future studies. Molecular studies should show if T. aspina sp.n. is evolutionarily related to morphologically similar species (e.g., T. nitidissimum), to the T. caespitum complex (the host; cf. Emery 1909), to slave makers (and thus a dulotic species or the link in the evolution of dulosis; cf. Kutter 1968), or to inquilines. Hopefully, field observa- tions will also throw light on its parasitic biology and help determine which type of social parasitism applies to this enigmatic ant species.

Taxonomic description of Tetramorium aspina sp.n. Etymology: Named after its strongly reduced propodeal spines. Because “aspina” is a noun in apposition, “a” is the correct ending. Type locality: Giresun-Dereli-Çamlı Village (Turkey; Fig. 2), 40.4767° N, 38.5108° E, 1953 meters above sea level, leg. K. Kiran, C. Karaman, and V. Aksoy, 12.VI.2012, 425 workers and 1 gyne. Type material: All type material from one nest, labe- led “TUR: 40.4767° N, 38.5108° E, Giresun-Dereli-Çamlı Village, 1953 m, subalpine Picea orientalis forest, K. Kiran, C. Karaman & V. Aksoy, 12.VI.2012 [/] 12/0859b”. Holo- type worker (Fig. 3a - c), 409 paratype workers, and 1 paratype gyne (Fig. 4a - c) in entomological collection of Bi- ological Department of Trakya University, Edirne (Turkey), five paratype workers in private collection of H.C. Wagner (Graz, Austria), three paratype workers in Senckenberg Naturkundemuseum Görlitz (Germany), three paratype workers in Natural History Museum London (Great Brit- ain), three paratype workers in Natural History Museum in Vienna (Austria), and one paratype worker in Tiroler Landesmuseum (Hall, Austria). Morphometric data of holotype in μm: CL = 703, CW = 691, dAN = 201, EL = 122, EW = 97, FL = 319, HFL = 538, ML = 861, MPPL = 252, MPSP = 267, MPST = 185, MtpW = 353, MW = 468, PEH = 250, PEL = 137, PEW = 237, PLSP = 150, PLST = 194, PnHL = 188, PoOc = 256, PPH = 244, PPL = 96, Ppss = 29, PPW = 278, PreOc = 182, PSW = 287, RTI = 274, SLd = 516, SPST = 108. Meristic data of holotype: MC1TG = 7.8, uni- lateral number of ommatidia = 30, unilateral number of teeth = 10, POTCos = 7.5. Fig. 4: Paratype gyne of Tetramorium aspina sp.n. in (a) full face, Putative host material: 150 workers of Tetramor- (b) dorsal, and (c) lateral views (photographer Leo Kuzmits). ium immigrans from same nest. Worker: Size: Smaller than in Tetramorium caespi- tum complex, CS = 646 ± 32 [590, 699] vs. 749 ± 64 [561, Sculpture on dorsum of head highly variable from 988] μm. nearly completely smooth with only few rudiments of Dorsum of head light brown, ventralwards from level rugulae to pronounced longitudinally rugulose. Vertex of frontal carinae continuously getting lighter and on eye completely smooth. Praeoculo-temporal area of head level and ventral of eye yellowish. Appendices, mesosoma, pronounced longitudinally rugulose, postoculo-temporal petiole, and postpetiole yellowish. First 20 - 60% of first area of head smooth or moderately rugulose, POTCos = gastral tergite yellow, posteriorly continuously getting 5.8 ± 2.2 [1.0, 9.3]. Dorsum of mesosoma smooth with only darker and last 10 - 50% light brown; remaining gaster small parts of longitudinal rugae or moderately rugulose, yellowish with sometimes light brown caudal margins lateral side of mesosoma with strongly pronounced rugae of tergites. and only parts of pronotum sometimes smooth; smooth

29 and shiny area on lateral side of propodeum rather small, Dorsum of head medium brown, ventralwards from Ppss = 27 ± 17 [10, 79]. Dorsum of petiolar and postpeti- level of frontal carinae continuously getting lighter and olar nodes completely smooth. Small connected reticulate on eye level and ventral of eye rather light brown. Appen- units scattered over 1st gastral tergite, MC1TG = 6.0 ± 1.2 dices light brown. Mesosoma light brown, but with dark [4.2, 8.2]. brown parts on mesonotum and scutellum, tegulae dark No sinuous hairs on ventral head. No erect hairs on brown. Petiole and postpetiole medium to dark brown. lateral side of head. A row of hairs at posterior margin First tergite of gaster medium brown, other tergites an- of head. Mesosoma hairs shorter than in Tetramorium teriorly light brown and posteriorly continuously getting caespitum complex, PnHL / CS = 0.208 ± 0.032 [0.153, darker and medium brown at caudal end. 0.270]. Moderately long erect hairs on dorsum of meso- Head frontal longitudinally rugulose, only area be- soma, petiole, postpetiole, and first gastral tergite. Erect tween ocelli and caudalmost part of head smooth and gaster hairs on further gastral segments only at caudal shiny. Lateral side of head with pronounced rugulosity, margins of tergites and sternites. POTCos = 11. Around half of mesonotum smooth and Head slightly elongated, CL / CW = 1.030 ± 0.020 [0.987, half longitudinally rugulose, smooth regions anteriorly 1.059]. 8.3 ± 0.9 [6.5, 10] teeth. Palp formula as Tetramo- and laterally. Scutellum longitudinally rugulose. Lateral rium immigrans: Maxillary palp with 4 segments, labial side of mesosoma with longitudinal rugae, pronotum, palp with 3. Scape rather short, SLd / CS = 0.739 ± 0.018 anepisternite, and mesopleuron partly smooth. [0.711, 0.770]. Twelve antennal segments. Distance be- No erect hairs on lateral side of head, but long hairs at tween frontal lobes larger than in T. caespitum complex, posterior margin of head and on dorsum of head. Mod- between antennal fossae moderate, and between tops of erately long mesosomal hairs, PnHL / CS = 0.242, short ridges between antennal fossae smaller than in T. caespi- mesonotum hairs, long hairs on scutellum, metanotum, tum complex, FL / CS = 0.458 ± 0.010 [0.442, 0.484], petiole (longest hair on petiole / CS = 0.305), and postpet- dAN / CS = 0.288 ± 0.006 [0.273, 0.300], RTI / CS = iole (longest hair on postpetiole / CS = 0.287). Erect gaster 0.381 ± 0.013 [0.362, 0.399]. Eye small and number of hairs only at caudal margins of tergites and sternites. ommatidia low, EL / CS = 0.165 ± 0.009 [0.147, 0.177], Head broader than in Tetramorium caespitum com- EW / CS = 0.133 ± 0.006 [0.121, 0.141], number of om- plex, CL / CW = 0.878. Scape longer than in T. caespitum matidia 23.4 ± 3.7 [18.0, 30.0]. Preocular distance rather complex, SLd / CS = 0.795. 8 teeth. 12 antennal segments. large, PreOc / CS = 0.268 ± 0.007 [0.258, 0.281], and Distance between frontal lobes larger than in T. caespitum postocular distance moderate, PoOc / CS = 0.403 ± 0.013 complex, between antennal fossae and between tops of an- [0.375, 0.426]. tennal fossae ridges moderate, FL / CS = 0.443, dAN / CS = Mesosoma longer and wider than in Tetramorium 0.279, RTI / CS = 0.370. Eye larger than in T. caespitum caespitum complex, ML / CS = 1.228 ± 0.021 [1.188, complex, EL / CS = 0.288, EW / CS = 0.244. Preocular dis- 1.274], MW / CS = 0.672 ± 0.015 [0.642, 0.698]. Prome- tance moderate, PreOc / CS = 0.202, and postocular distance sonotal dorsum convex, metanotal groove moderately deep smaller than in T. caespitum complex, PoOc / CS = 0.336. to deep. Propodeal syndrome common. Metapleuron and Mesosoma shorter and narrower than in Tetramorium propodeum wider than in T. caespitum complex but (be- caespitum complex, ML / CS = 1.859, MW / CS = 1.067. cause of propodeal syndrome) highly variable, MtpW / CS Propodeal spiracle distance PSW / CS = 0.683. Hind fe- = 0.508 ± 0.032 [0.446, 0.558], PSW / CS = 0.393 ± 0.050 mur moderately long, HFL / CS = 0.972. Propodeal spines [0.302, 0.471]. Hind femur short, HFL / CS = 0.751 ± 0.018 shorter than in T. caespitum complex, MPSP / CS = 0.556, [0.718, 0.776]. Propodeal spine completely missing or rudi- SPST / CS = 0.272, PLSP / CS = 0.269, SPWI / CS = 0.441. mentary, MPSP / CS = 0.395 ± 0.018 [0.368, 0.430], SPST Distance from anteroventralmost point of metapleuron / CS = 0.166 ± 0.012 [0.155, 0.200], PLSP / CS = 0.206 ± to propodeal spiracle and propodeal lobe smaller than in 0.019 [0.177, 0.245]. Distance from anteroventralmost T. caespitum complex, MPST / CS = 0.344, MPPL / CS = point of metapleuron to propodeal spiracle and propodeal 0.446. Distance between propodeal lobe and propodeal lobe larger than in T. caespitum complex, MPST / CS = spiracle rather large, PLST / CS = 0.351. 0.269 ± 0.012 [0.252, 0.296], MPPL / CS = 0.374 ± 0.012 Petiole and postpetiole wider, lower, and shorter than [0.358, 0.401]. Distance between propodeal lobe and in Tetramorium caespitum complex, PEW / CS = 0.505, propodeal spiracle larger than in T. caespitum complex, PEH / CS = 0.458, PEL / CS = 0.224, PPW / CS = 0.715, PLST / CS = 0.287 ± 0.013 [0.262, 0.312]. PPH / CS = 0.448, PPL / CS = 0.155. Median petiole in- Postpetiole and petiole wider, higher, and shorter section depth / CS = 0.027, median postpetiole insection than in Tetramorium caespitum complex, PPW / CS = depth / CS = 0.008. 0.421 ± 0.021 [0.392, 0.476], PEW / CS = 0.342 ± 0.025 Differential diagnosis of workers:The character [0.270, 0.380], PEH / CS = 0.373 ± 0.011 [0.358, 0.401], combination of yellowish color and strong reduction of PPH / CS = 0.371 ± 0.014 [0.350, 0.407], PEL / CS = propodeal spines allows differentiation from allTetramor - 0.211 ± 0.008 [0.196, 0.225], PPL / CS = 0.139 ± 0.008 ium species in Europe, Mediterranean basin, and adjacent [0.119, 0.154]. regions. Differentiation fromT. nitidissimum workers (type Gyne: Size: Smaller than in Tetramorium caespitum locality: Firyuza, 25 km W Ashgabat, Turkmenistan) pos- complex, CS = 1073 μm. sible by three steps: (i) Tetramorium aspina sp.n. exhibits

30 FL / CL dAN / CL 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0

a b

MPPL / CL PLST / CL 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0

c d

Fig. 5: Diagnostic characters of type workers of Tetramorium nitidissimum Pisarski, 1967 (red; n = 2) and Tetramorium aspina sp.n. (blue; n = 18): (a) FL / CL, (b) dAN / CL, (c) MPPL / CL, and (d) PLST / CL.

Acknowledgments a row of long hairs at posterior margin of head (see Fig. 3a). Tetramorium nitidissimum does not show such long Bernhard Seifert (Görlitz) provided the microscope used hairs. (ii) Frontal carinae and antennal fossae of T. niti- for this study; Alexander Eder (Graz) repaired an elec- dissimum type-workers are narrower (FL / CL = 0.332 - tronic damage of the microscope. Leo Kuzmits (Graz) 0.337, dAN / CL = 0.246 - 0.247, n = 2) than in T. aspina took photographs of type material, the native speakers sp.n. (FL / CL = 0.451 ± 0.010 [0.435, 0.470], dAN / CL = Phil J. Attewell (Boreham Wood) and Steven Weiss (Graz) 0.284 ± 0.007 [0.269, 0.296], n = 18; Fig. 5a, b). (iii) Dis- proofread the manuscript. Florian M. Steiner (Innsbruck), tances from dorsocaudalmost point of propodeal lobe to Christian Rabeling (Tempe), Marek L. Borowiec (Tempe), most anteroventral point of metapleuron and to center of and two anonymous reviewers provided input that helped propodeal spiracle are smaller (MPPL / CL = 0.291 - 0.309, improving the manuscript. The research of HCW was fi- PLST / CL = 0.209 - 0.226) than in T. aspina sp.n. (MPPL / CL = nancially supported by the Austrian Science Fund (FWF, 0.369 ± 0.013 [0.351, 0.398], PLST / CL = 0.283 ± 0.013 P23409), the Turkish authors by TUBITAK (THE SCIEN- [0.259, 0.309] n = 18; Fig. 5c, d). TIFIC AND TECHNOLOGICAL RESEARCH COUNCIL Distribution: Only known from type locality. OF TURKEY, project number 111T811). Biology: Putative social parasite of T. immigrans. References Likely monogynous. Small eyes and yellowish color indi- cate subterranean activity. Blanchard, B.D. & Moreau, C.S. 2017: Defensive traits exhibit Ecology: The type locality is a subalpine, sparse, an evolutionary trade-off and drive diversification in ants. and almost 100-year-old forest with large sun-exposed – Evolution 71: 315-328. treeless areas. The nest was located on a stony and rocky Bolton, B. 1995: A new general catalogue of the ants of the east slope with a 50 - 55° inclination. Herb layer plants are world. – Harvard University Press, Cambridge, MA, 504 pp. Anthemis sp., Daucus sp., Malva sp., Medicago sp., Myo- Borowiec, L. 2014: Catalogue of ants of Europe, the Mediterra- sotis sp., Poaceae species, Rosa sp., Rubus sp., Taraxacum nean basin and adjacent regions: (Hymeno­ptera: Formicidae). sp., Trifolium sp., Verbascum sp., and Veronica sp. Cam- – Biologica Silesiae, Wrocław, Poland, 340 pp. ponotus aethiops (Latreille, 1798), Formica cunicularia Borowiec, L., Galkowski, C. & Salata, S. 2015: What is Latreille, 1798, F. fusca Linnaeus, 1758, Lasius alienus Tetramorium semilaeve André, 1883? (Hymeno­ptera: Formicidae). – ZooKeys 512: 39-62. (Foerster, 1850), Lasius flavus (Fabricius, 1782), Man- ica rubida (Latreille, 1802), Messor structor complex, Borowiec, L., Galkowski, C. & Salata, S. 2016: Redescrip- tion of Tetramorium atlante Cagniant, 1970, new sta- Proformica pilosiscapa Dlussky, 1969, Temnothorax art- tus (Hymeno­ptera: Formicidae: Myrmicinae). – Annales vinensis Seifert, 2006, Temnothorax unifasciatus (La- Zoologici 66: 43-52. treille, 1798), Tetramorium immigrans, Tetramorium Buschinger, A. 2009: Social parasitism among ants: a review cf. impurum, and a further non-identified Tetramorium (Hymeno­ptera: Formicidae). – Myrmecological News 12: sp. were also recorded from the same locality. 219-235.

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